The present application relates to a semiconductor structure and a method of forming the same. More particularly, the present application relates to a three-dimensional (3D) bonded semiconductor structure having enhanced mechanical bonding strength and electrical performance. The present application also relates to a method of forming such a 3D bonded semiconductor structure.
Three-dimensional (3D) integration is critical in current and in future technology development. Traditionally, oxide-oxide bonding is performed to physically connect two wafers and, thereafter, through-silicon-vias (TSVs) are formed to electrically connect the two wafers.
In the most advanced 3D integration technology development, oxide-oxide and metal to metal (e.g., Cu—Cu) bonding are performed simultaneously. Accordingly, both oxide/oxide bonding strength and metal/metal contact are critical in order to meet the mechanical integrity requirement as well as the electrical performance. Presently, there is no known method that enhances both the metal to metal (e.g., Cu—Cu) mechanical bonding strength and the electrical performance of a 3D bonded semiconductor structure.